Pratt & Whitney Wankel prototype to test by June

A Wankel engine prototype should be under test by June for a Pratt & Whitney effort to deliver high specific power unmanned air vehicle engines.

Work is now under way on building the prototype. The goal is to achieve a specific power of 3.28kW/kg (2hp/lb), with a successful test in this quarter expected to lead to the development and fabrication of a flight weight version of the air-cooled engine, which is called Enduro-core and will use diesel.

The P&W Wankel is combining the small and large stator rotors on to a single shaft to help improve efficiency. With an undisclosed UAV provider for a customer, the engine is being aimed at a class of unmanned vehicles similar to the AAI Shadow.

"A lot of engines don't have a long life. We are aiming for better [lifecycle]," says Pratt & Whitney Alabama operations' general manager, Rick Bachtel, who also oversees future programmes.

He says another market for the engine is compact power for the military. The work is also involving power management technology from P&W's United Technologies' sister companies. Bachtel's team originally looked at small high-speed turbines because of Rocketdyne's experience with turbopumps, but he says "it didn't work out".

The prototype is being built by Andrews Space. The company has rapid prototype capability and P&W wants to learn from Andrews techniques of incorporating the small company entrepreneurial culture in its large organisation.